Carotenoids are a class of natural fat-soluble pigments found principally in plants, algae, and photosynthetic bacteria, where they play a critical role in the photosynthetic process. They also occur in some non-photosynthetic bacteria, yeasts, and molds, where they carry out a protective function against damage by light and oxygen. Although animals appear to be incapable of synthesizing carotenoids, many animals incorporate carotenoids from their diet. Within animals, carotenoids provide bright coloration, serve as antioxidants, and can be a source for vitamin A activity (Ong and Tee 1992; Britton et al. 1995).
Carotenoids are defined by their chemical structure. The majority carotenoids are derived from a 40-carbon polyene chain, which could be considered the backbone of the molecule. This chain may be terminated by cyclic end-groups (rings) and may be complemented with oxygen-containing functional groups. The hydrocarbon carotenoids are known as carotenes, while oxygenated derivatives of these hydrocarbons are known as Xanthophylls. Beta-carotene, the principal carotenoid in carrots, is a familiar carotene, while Lutein, the major yellow pigment of marigold petals, is a common xanthophyll.
Xanthophylls have been proven scientifically to reduce the risk of age related macular degeneration (Moeller S M, Jacques P F, Blumberg J B “The potential role of dietary Xanthophylls in cataract and age related macular degeneration,” Journal of the American College of Nutrition, 2000; 19: 522S-527S), control over LDL cholesterol (Chopra M., Thurnham D I, “Effect of Lutein on oxidation of low density lipoproteins (LDL) in vitro”, Proceedings of the Nutrition Society, 1994; 53: 1993, #18A.), prevention of Coronary heart diseases (Howard A N, Williams N R, Palmer C R, Cambou J P, Evans A E, Foote J W, et al., “Do hydroxy-carotenoids prevent coronary heart disease”) and free radicals scavenging and immunity enhancing (Chew B P, Wong M W, Wong T S, “Effects of Lutein from Marigold extract on immunity and growth of mammary tumors in mice,” Anticancer Research, 1996; 16: 3689-3694).
Lutein (β-ε-carotene-3-3′-diol) and Zeaxanthin (β-β-carotene-3-3′-diol) belong to Xanthophylls group in the carotenoids family with highly reactive hydroxyl groups which cannot be synthesized by humans and animals.
U.S. Pat. No. 5,382,714 discloses process for isolation of pure lutein comprising from saponified marigold oleoresin containing free lutein.
U.S. Pat. No. 6,262,284 discloses process for extracting, saponifying, and isolating lutein and zeaxanthin, and a mixture of several rare carotenoids in high purity from plants.
U.S. Pat. No. 5,648,564 discloses a process for saponification of the marigold oleoresin with an aqueous alkali diluted with propylene glycol, resulting in the formation of lutein crystals.
U.S. Pat. No. 6,380,442 discloses a process of obtaining carotenoids from marigold oleoresin through hydrolysis by using iso-propyl alcohol with saponification. Further, the process involves cooling the reaction mixture to room temperature.
U.S. Pat. No. 6,504,067 discloses a process to obtain xanthophyll concentrates by refining the marigold oleoresin with sodium carbonate followed by neutralization, wherein the refined oleoresin was saponified using aqueous alkali.
WO 2006/114794 describes a procedure to isolate carotenoids, predominantly lutein from marigold flower petals.
U.S. Pat. No. 5,876,782 discloses in situ process for converting non-free form xanthophylls to free xanthophylls by transesterification of acyl-xanthophylls present in the biological material of the plant.
U.S. Pat. No. 6,743,953 describes a process of extraction of xanthophylls from dried marigold petals using hexane as solvent, involving saponification up to 3 hrs, subjecting the product to heating at 70° C. for a long time which may result in degenerated oxidative products in the saponified mass.
JP 113222708 A describes a process for isolating lutein from marigold oleoresin by saponification.
U.S. Pat. No. 6,784,351 discloses a marigold plant whose flower petals, leaves contain one or more of an enhanced zeaxanthin ratio, an enhanced neoxanthin plus violaxanthin ratio, an enhanced β-carotene ratio, an enhanced α-cryptoxanthin ratio, an enhanced phytoene ratio or an enhanced phytofluene ratio relative to that ratio in a non-mutant marigold. Also disclosed are methods of preparing such plants, oleoresins and comestible materials that have such carotenoid ratios.
However, there is a need for a process for isolation of carotenoids crystals wherein the dried plant meal is directly contacted with alcohol and wherein the carotenoids crystals thus obtained comprises xanthophylls such as lutein, zeaxanthin and low levels of β-carotene and cryptoxanthin.
These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description and appended claims.